def count_valid_passwords(lines: List[PasswordPolicy],
validator: Callable[[PasswordPolicy], bool]):
return sum(1 for line in lines if validator(line))
def validator1(policy: PasswordPolicy):
return policy.start <= Counter(
policy.password)[policy.character] <= policy.end
def validator2(policy: PasswordPolicy):
password, character = policy.password, policy.character
start, end = policy.start, policy.end
return (password[start - 1] == character) ^ (password[end - 1]
== character)
def parse(policy: str) -> PasswordPolicy:
match = re.match(r'(\d+)-(\d+) (\w): (\w+)', policy)
return PasswordPolicy(int(match.group(1)), int(match.group(2)),
match.group(3), match.group(4))
if __name__ == "__main__":
password_policies = reader.read_lines("./input.txt", parse)
print(count_valid_passwords(password_policies, validator2))
all_seats = {
get_seat_id(seat_position): seat_position
for seat_position in all_seat_positions
}
for row in range(1, ROW_MAX + 1):
for col in range(COL_MAX + 1):
if (row, col) not in all_seat_positions:
seat_id = get_seat_id((row, col))
if seat_id - 1 in all_seats and seat_id + 1 in all_seats:
return seat_id
if __name__ == "__main__":
data = reader.read_lines(
"./input.txt",
lambda x: str(x).replace("B", INCREASE).replace("R", INCREASE))
passes = [BoardingPass(line[:7], line[7:]) for line in data]
# Part 1
print(
max(
get_seat_id(get_seat_position(boarding_pass))
for boarding_pass in passes))
# Part 2
print(find_own_seat_id(passes))
"pid": lambda id: len(id) == 9 and id.isnumeric(),
}
def parse_passport(raw_passport: str) -> Dict[str,str]:
passport = {}
for field in RULES:
if match := re.match(f".*{field}:([\S]+)", raw_passport):
passport[field] = match.group(1)
return passport
def is_valid_passport1(passport: Dict[str, str]) -> bool:
return all(field in passport for field in RULES)
def is_valid_passport2(passport: Dict[str, str]) -> bool:
return all(key in passport and RULES[key](passport[key]) for key in RULES)
if __name__ == "__main__":
data = reader.read_lines("./input.txt", lambda x: str(x).replace("\n", " ") if x != "\n" else x)
raw_passports = "".join(data).split("\n") # ugly hack
passports = [parse_passport(raw_passport) for raw_passport in raw_passports]
print(sum(1 for passport in passports if is_valid_passport1(passport)))
print(sum(1 for passport in passports if is_valid_passport2(passport)))
from typing import List
import math
import reader
def count_trees(tree_map: List[str], right: int, down: int) -> int:
count = 0
for i in range(len(tree_map) // down):
y = i * down
x = (right * i) % (len(tree_map[0]) - 1)
count += tree_map[y][x] == "#"
return count
if __name__ == "__main__":
data = reader.read_lines("./input.txt")
slopes = [(1, 1), (3, 1), (5, 1), (7, 1), (1, 2)]
tree_counts = [count_trees(data, right, down) for right, down in slopes]
print(math.prod(tree_counts))
def two_sum(nums: List[int], target: int) -> Union[Tuple[int, int], None]:
ht = {}
for i, v in enumerate(nums):
if v in ht:
return i, ht[v]
else:
ht[target - v] = i
return None
def three_sum(nums: List[int],
target: int) -> Union[Tuple[int, int, int], None]:
ht = {target - v: i for i, v in enumerate(nums)}
for i in range(len(nums) - 1):
for j in range(i + 1, len(nums)):
pair_sum = nums[i] + nums[j]
if pair_sum in ht and ht[pair_sum] not in (i, j):
return i, j, ht[pair_sum]
return None
if __name__ == "__main__":
nums = reader.read_lines("./input.txt", int)
if (answer := three_sum(nums, 2020)) is not None:
print(prod([nums[x] for x in answer]))